Studies on Tapeworm Physiology

1949 ◽  
Vol 26 (1) ◽  
pp. 1-15
Author(s):  
J. D. SMYTH
Keyword(s):  
Bacterial Infections ◽  
Detrimental Effect ◽  
Horse Serum ◽  
Body Cavity ◽  
The Body ◽  
Nutrient Media ◽  
Medium Strength ◽  
By Products ◽  
Histochemical Examination

1. Plerocercoid larvae of the pseudophyllidean cestode Ligula intestinalis from the body cavity of roach, were cultured in vitro at 40°C. in a variety of saline and nutrient media. About 65% of such cultures were aseptic. 2. During cultivation, larvae produced acid by-products (unidentified) and the pH fell rapidly. 3. The presence of these acid by-products slowed down development, or, if present in sufficient quantity, caused death. 4. In order to obtain development in nutrient media in a period (3 days) comparable to that required in a bird (the normal host) it was necessary to renew the medium 24-hourly. 5. 6% of the eggs produced from a worm cultured in horse serum were fertile. Fertile eggs were never obtained from larvae cultured in any other media. 6. Certain bacterial infections had no apparent detrimental effect on development, but others were toxic. 7. Some larvae underwent development in non-nutrient medium (¾ strength Locke's solution). The exact conditions under which this occurred was not determined. 8. Fragments (3 cm. long), of larvae or larvae with either scolex or posterior half removed, underwent development to the stage of oviposition in nutrient media. 9. Histochemical examination revealed that the plerocercoid larvae were almost fat-free. During cultivation, very large quantities of cytoplasmic fat were produced the quantity being proportional to the duration of cultivation. Fat was produced even under starvation conditions (i.e. during cultivation in saline) and can be considered a metabolic by-product. 10. The fresh plerocercoid contained great quantities of glycogen in the parenchyma and muscle regions. After cultivation in nutrient or saline media, considerable quantities were still present.

scholarly journals Imaging Sensitive and Drug-Resistant Bacterial Infection with [11C]-TMP: In Vitro and First-in-Human Evaluation

2021 ◽  
Author(s):  
Iris K Lee ◽  
Daniel A Jacome ◽  
Joshua K Cho ◽  
Vincent Tu ◽  
Anthony Young ◽  
...  
Keyword(s):  
Bacterial Infection ◽  
Mammalian Cells ◽  
Bacterial Infections ◽  
The Body ◽  
Response Monitoring ◽  
Drug Resistant ◽  
Bacterial Strains ◽  
Critical Question ◽  
In Vitro Uptake

Recently, several molecular imaging strategies have developed to image bacterial infections in humans. Nuclear approaches, specifically positron emission tomography (PET), affords sensitive detection and the ability to non-invasively locate infections deep within the body. Two key radiotracer classes have arisen: metabolic approaches targeting bacterial specific biochemical transformations, and antibiotic-based approaches that have inherent selectivity for bacteria over mammalian cells. A critical question for clinical application of antibiotic radiotracers is whether resistance to the template antibiotic abrogates specific uptake, thus diminishing the predictive value of the diagnostic test. We recently developed small-molecule PET radiotracers based on the antibiotic trimethoprim (TMP), including [11C]-TMP, and have shown their selectivity for imaging bacteria in preclinical models. Here, we measure the in vitro uptake of [11C]-TMP in pathogenic susceptible and drug-resistant bacterial strains. Both resistant and susceptible bacteria showed similar in vitro uptake, which led us to perform whole genome sequencing of these isolates to identify the mechanisms of TMP resistance that permit retained radiotracer binding. By interrogating these isolate genomes and a broad panel of previously sequenced strains, we reveal mechanisms where uptake or binding of TMP radiotracers can potentially be maintained despite the annotation of genes conferring antimicrobial resistance. Finally, we present several examples of patients with both TMP-sensitive and drug-resistant infections in our first-in-human experience with [11C]-TMP. This work underscores the ability of an antibiotic radiotracer to image bacterial infection in patients, which may allow insights into human bacterial pathogenesis, infection diagnosis, and antimicrobial response monitoring.

Studies on Tapeworm Physiology

1946 ◽  
Vol 23 (1) ◽  
pp. 47-70 ◽  
Author(s):  
J. D. SMYTH
Keyword(s):  
Histological Examination ◽  
Gasterosteus Aculeatus ◽  
Body Cavity ◽  
Final Host ◽  
The Body ◽  
Normal Behaviour ◽  
The Mean ◽  
Peptone Broth

A technique has been elaborated that enabled the plerocercoid larvae of Schistocephalus solidus to be removed from the body cavity of Gasterosteus aculeatus without bacterial contamination. Larvae were cultured in plugged test-tubes under completely aseptic conditions in a variety of balanced salines, glucose salines and nutrient peptone broth. The most successful results were obtained with peptone broth at room temperatures (16-19° C) in which plerocercoids remained active and showed normal behaviour for periods up to 300 days. In ¾ strength Locke's solution, which was found by experiment to be approximately isotonic with Schistocephalus (δ = -0.44 ± 0.02° C), the mean period of normal behaviour was 114 days. In the remaining saline and saline-glucose media, the mean viability and period of normal behaviour was considerably less. In the plerocercoid, histological examination revealed that the genitalia are in an immature condition. During cultivation at room temperatures, the genitalia remained in this undifferentiated condition and showed no signs of undergoing spermatogenesis, oogenesis or vitellogenesis. Plerocercoids were induced to develop into sexually mature adults by raising the temperature of cultivation in peptone broth to 40° C. (i.e. the body temperature of the final host in the natural life cycle). Oviposition took place after 48-60 hr. at this temperature, and histological examination revealed that spermatogenesis, oogenesis, vitellogenesis and shell formation had taken place in a normal manner. The viability of artificially matured Schistocephalus was 4-6 days in vitro--a period equivalent to the viability of the adult in vivo. The eversion of the cirris was observed in each proglottid after 40 hr. cultivation at 40° C. During the sexual process the cirris everted and invaginated at the rate of about once per second. Cross-fertilization between segments of the same worm or with segments of another worm was not observed. Except for one specimen in ¾ strength Locke's solution which underwent spermatogenesis and partial vitellogenesis, larvae cultured in salines or glucose salines at 40° C. died within 1-3 days without further development. Attempts to hatch out the eggs produced by the cultivation of larvae in peptone broth at 40° C. proved unsuccessful. Histological examination revealed that spermatozoa had not been taken into the vagina. It was concluded that the eggs were not fertilized owing to the failure of normal copulation to take place.

Studies on tapeworm physiology

Parasitology ◽  
1947 ◽  
Vol 38 (3) ◽  
pp. 173-181 ◽  
Author(s):  
J. D. Smyth
Keyword(s):  
Body Cavity ◽  
The Body ◽  
Cell Stage ◽  
Normal Manner ◽  
Receptaculum Seminis ◽  
Larval Condition ◽  
Aseptic Conditions ◽  
Sexually Mature ◽  
Peptone Broth

The plerocercoid larvae of the pseudophyllidean cestode Ligula intestinalie have been removed from the body-cavity of the roach, Rutilua rutilus, and cultured in vitro under aseptic conditions, using a technique similar to that successfully applied to Schistocephalus solidus.In the larval condition, the genitalia are in a primitive, immature condition, with the testes, ovaries and yolk-glands only partially developed.Larvae were cultured in peptone-broth in plugged tubes at a temperature of 40° C, i.e. the body temperature of birds in which the plerocercoids normally develop into adult worms.Three of the nine larvae used became sexually mature after 7 days' cultivation, and oviposition took place. Copulation between successive genitalia of the same worm or with genitalia of another worm in the same culture tube was not observed.Histological examination revealed that spermatogenesis, oogenesis, vitellogenesis and shell formation had apparently taken place in a normal manner. The testes contained giant polyploid cells as well as mature spermatozoa. The receptaculum seminis contained no spermatozoa, from which it was concluded that fertilization had not taken place. This was confirmed by the fact that attempts to hatch out the eggs were unsuccessful. The unfertilized eggs, however, underwent parthenogenic development within the uterus as far as the two-cell stage. Of the remaining six larvae, four developed sufficiently to undergo eversion of the cirrus, but died without oviposition taking place.

First report of a gryporhynchid tapeworm (Cestoda: Cyclophyllidea) from New Zealand and from an eleotrid fish, described from metacestodes and in vitro-grown worms

2011 ◽  
Vol 86 (4) ◽  
pp. 453-464 ◽  
Author(s):  
B. Presswell ◽  
R. Poulin ◽  
H.S. Randhawa
Keyword(s):  
New Zealand ◽  
First Record ◽  
Small Subunit ◽  
Body Cavity ◽  
The Body ◽  
Species Determination ◽  
Fish Family ◽  
Rdna Sequences ◽  
Stage Of Development

AbstractMetacestodes are often found in the body cavity of the common bully (Gobiomorphus cotidianus McDowall), from freshwater habitats in Otago, New Zealand. Identification of metacestodes relies only on the number, size and shape of the rostellar hooks. To attempt species determination, we cultivated metacestodes in vitro for up to 23 days, during which they matured to at least the male stage of development, although female organs were not discernable. Identified as members of the genus Paradilepis Hsü, 1935 (family Gryporhynchidae), these specimens are compared to previously described species, in particular P. minima (Goss, 1940), from Australia, the closest species, both geographically and morphologically. Although the size of scolex, suckers and proglottids differ significantly from those of P. minima, we are cautious about interpreting ‘adults’ grown in vitro, because we are unsure whether the artificial conditions alter development. For this reason, and because of the lack of female organs, we refrain from erecting a new species, and refer to the specimens as Paradilepis cf. minima until such time as the adults are found in the definitive host. With this proviso we present here a description of the in vitro-grown worms and the metacestodes as a preliminary study of this cestode. A molecular analysis of small subunit (SSU) rDNA sequences, shows the position of P. cf. minima and another gryporhynchid, Neogryporhynchus cheilancristrotus (Wedl, 1855), to be equivocal, but confirms their exclusion from the Dilepididae and Hymenolepididae. This is the first record of a gryporhynchid from New Zealand, and the first from the fish family Eleotridae.

scholarly journals In vitro and in vivo antibacterial activities of CS-940, a new 6-fluoro-8-difluoromethoxy quinolone.

1996 ◽  
Vol 40 (5) ◽  
pp. 1201-1207 ◽  
Author(s):  
N Masuda ◽  
Y Takahashi ◽  
M Otsuki ◽  
E Ibuki ◽  
H Miyoshi ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Oral Treatment ◽  
Horse Serum ◽  
Antibacterial Activities ◽  
Inoculum Size ◽  
The Other ◽  
Gram Positive Bacteria ◽  
Systemic Infections

The in vitro and in vivo activities of CS-940, a new 6-fluoro-8-difluoromethoxy quinolone, were compared with those of ciprofloxacin, tosufloxacin, sparfloxacin, and levofloxacin. The in vitro activity of CS-940 against gram-positive bacteria was nearly equal to or greater than those of the other quinolones tested. In particular, CS-940 was two to eight times more active against methicillin-resistant Staphylococcus aureus than the other quinolones, at the MIC at which 90% of the clinical isolates are inhibited. Against gram-negative bacteria, the activity of CS-940 was comparable to or greater than those of tosufloxacin, sparfloxacin, and levofloxacin, while it was lower than that of ciprofloxacin. The activity of CS-940 was largely unaffected by medium, inoculum size, or the addition of horse serum, but it was decreased under acidic conditions, as was also seen with the other quinolones tested. CS-940 showed potent bactericidal activity against S. aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. In oral treatment of mouse systemic infections caused by S. aureus, Streptococcus pneumoniae, Streptococcus pyogenes, E. coli, K. pneumoniae, Serratia marcescens, and P. aeruginosa, CS-940 was more effective than ciprofloxacin, sparfloxacin, and levofloxacin against all strains tested. Against experimental pneumonia with K. pneumoniae in mice, CS-940 was the most effective of all the quinolones tested. These results suggest that CS-940 may be effective in the therapy of various bacterial infections.

A new chytridiomycete parasitizing the tardigrade Milnesium tardigradum

1985 ◽  
Vol 63 (9) ◽  
pp. 1525-1534 ◽  
Author(s):  
Ruth Ann Dewel ◽  
Jerry D. Joines ◽  
John J. Bond
Keyword(s):  
Life Cycle ◽  
Nutrient Medium ◽  
Body Cavity ◽  
The Body ◽  
Nutrient Agar ◽  
Nutrient Media ◽  
Central Mass ◽  
Host Death

The life cycle of a chytridiomycete, Sorochytrium milnesiophthora gen. et sp. nov., infecting the tardigrade Milnesium tardigradum, is described. The zoospores are posteriorly uniflagellate and ovoid, and possess a central mass similar to a nuclear cap. To initiate an endobiotic infection they attach to the cuticle of the host, encyst, and generate an appressorium. The appressorium forms a penetration tube which crosses the cuticle to the epidermis and enlarges at the tip into a spherical thallus. Concomitantly, vacuoles replace the cytoplasm of the cyst and appressorium. As the thallus enlarges, it moves into the body cavity and cleaves into segments. The segments separate and round up into incipient sporangia. The incipient sporangia develop branching rhizoids in conjunction with host death. After a period of growth the sporangia form inoperculate exit papillae which penetrate the host cuticle. Zoospores exit individually and fully formed. The fungus can develop a polycentric phase when freshly collected, dead hosts containing sporangia are cultured in habitat water or on nutrient agar. The growth is extramatrical, covering the surface of the old host. It is rhizoidal, branching, and nonseptate with numerous intercalate incipient sporangia bearing rhizoids. On nutrient media the thallus grows indefinitely while in habitat water the incipient sporangia mature and discharge motile spores. The spores frequently have two to five flagella and are larger than those of the endobiotic colonial phase. A similar polycentric growth develops when motile spores are isolated on nutrient medium and suggests that the extramatrical growth on the host originates from encysted spores.

The egg sorting function of the uterine bell of Polymorphus minutus (Acanthocephala)

Parasitology ◽  
1970 ◽  
Vol 61 (1) ◽  
pp. 111-126 ◽  
Author(s):  
P. J. Whitfield
Keyword(s):  
Adult Female ◽  
Muscular Activity ◽  
Body Cavity ◽  
Final Host ◽  
The Body ◽  
Duct Cells ◽  
Age Structures

An adult female Polymorphus minutus releases only mature eggs into the intestine of its final host. These eggs come from the pool of eggs in the body cavity of the worm which contains only about 30% of mature eggs, the rest being immature. An analysis of the age structures of the egg populations in the body cavity and the uterus shows that an assortment of mature and immature eggs has taken place as the eggs pass from the body cavity to the uterus. The uterus contains only mature eggs and these are the eggs which are about to be released. The only pathway whereby eggs can enter the uterus from the body cavity is through the uterine bell. This suggests that it is the uterine bell which is able to select mature eggs from the mixture of eggs in the body cavity.A uterine bell in vitro engages in precisely patterned muscular activity which propels eggs through its branching lumen. In one part of the bell (the grooves between the median wall cells and the lappets of the uterine duct cells), the patterned muscular activity passes mature eggs into the uterus and immature eggs back into the body cavity to complete their development. The greater length of mature eggs seems to be the character which enables them to be ‘recognized‘ by the uterine bell.

scholarly journals In vitro and in vivo antibacterial efficacies of CFC-222, a new fluoroquinolone.

1997 ◽  
Vol 41 (10) ◽  
pp. 2209-2213 ◽  
Author(s):  
J H Kim ◽  
J A Kang ◽  
Y G Kim ◽  
J W Kim ◽  
J H Lee ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Protective Efficacy ◽  
Horse Serum ◽  
The Other ◽  
Infection Model ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli

CFC-222 is a novel fluoroquinolone containing a C-7 bicyclic amine moiety with potent antibacterial activities against gram-positive, gram-negative, and anaerobic organisms. We compared the in vitro and in vivo activities of CFC-222 with those of ciprofloxacin, ofloxacin, and lomefloxacin. CFC-222 was more active than the other fluoroquinolones tested against gram-positive bacteria. CFC-222 was particularly active against Streptococcus pneumoniae (MIC at which 90% of isolates are inhibited [MIC90], 0.2 microg/ml), Staphylococcus aureus (MIC90, 0.2 microg/ml for ciprofloxacin-susceptible strains), and Enterococcus faecalis (MIC90, 0.39 microg/ml). Against Escherichia coli and other members of the family Enterobacteriaceae, CFC-222 was slightly less active than ciprofloxacin (MIC90s for E. coli, 0.1 and 0.025 microg/ml, respectively). The in vitro activity of CFC-222 was not influenced by inoculum size, medium composition, or the presence of horse serum. However, its activity was decreased significantly by a change in the pH of the medium from 7.0 to 6.0, as was the case for the other quinolones tested. The in vivo protective efficacy of CFC-222 by oral administration was greater than those of the other quinolones tested in a mouse model of intraperitoneally inoculated systemic infection caused by S. aureus. CFC-222 exhibited efficacy comparable to that of ciprofloxacin in the same model of infection caused by gram-negative organisms, such as E. coli and Klebsiella pneumoniae. In this infection model, CFC-222 was slightly less active than ciprofloxacin against Pseudomonas aeruginosa. These results suggest that CFC-222 may be a promising therapeutic agent in various bacterial infections.

scholarly journals Studies on the Life Cycle of Some New Zealand Anisakidae (Nematoda)

2021 ◽  
Author(s):  
◽  
Rosemary Jennifer Hurst
Keyword(s):  
Life Cycle ◽  
New Zealand ◽  
Body Cavity ◽  
The Body ◽  
In Vitro Cultivation ◽  
Free Living ◽  
Larval Stages ◽  
Factors Influencing ◽  
Phocarctos Hookeri

<p>The life cycle of Anisakis simplex in New Zealand waters is described from observations on the morphology, distribution and behaviour of free-living and parasitic stages. Comparison with the life cyles of two other anisakids, Phocanema decipiens Myers 1959 and Thynnascaris adunca Rudolphi 1802 shows differences in distribution, degrees of host specificity, the status of invertebrate hosts, the factors influencing infestation levels of teleost hosts, and the location and pathological effects of infestation. Larval stages occurring in intermediate and paratenic hosts were identified by comparison of larval and adult morphometrics. A. simplex larvae were also positively identified by in vitro cultivation through to adults. Some morphometric variations compared to overseas descriptions are apparent. The ventriculus of A. simplex larvae is shorter relative to body length and the intestinal caecum of P. decipiens is longer relative to ventriculus length. Egg and free-living larval stages were obtained from in vitro cultivation of (A. simplex) and collection of eggs from mature adults from definitive hosts (T. adunca). Eggs of P. decipiens were not obtained. Eggs of A. simplex and T. adunca hatch in 8-11 days at 15 [degrees] C. A. simplex eggs hatch in 6 days at a temperature of 22 [degrees] C and did not hatch in 16 days at 10 [degrees] C. Eggs and free-living stage III larvae of A. simplex and T. adunca are similar in morphology with little differentiation of internal structures. Examination of the stomach contents of pelagic fish infested with anisakids indicated that possible intermediate hosts of A. simplex are the euphausiid Nyctiphanes australis and the decapod Munida gregaria. Possible hosts of T. adunca and M. gregaria are a wide variety of smaller zooplanktonic groups, e.g. decapod larvae and copepods. Larvae of A. simplex were found in one of 8850 N. australis; larvae of T. adunca were found in 69 of 3999 chaetognaths (Sagitta spp.) a medusa and a decapod larva. These larvae are morphologically similar to Stage III larvae from teleosts. No anisakids were found in 3956 Euphausia spp., 1147 M. gregaria and 740 prawns. Twenty five T. adunca larvae and adults were found in 818 freshly eaten M. gregaria in teleost stomachs, indicating that this invertebrate may act as a paratenic and a definitive host. Experimental infection of N. australis and M. gregaria with stage II larvae of A. simplex and T. adunca was unsuccessful. The location of anisakid infestation in three pelagic teleost species, Thyrsites atun, Trachurus novaezelandiae and Trachurus declivis is described. A. simplex larvae are found mainly in the body cavity of all species, at the posterior end of the stomach, with less than one percent occurring in the musculature. Distribution of A. simplex larvae does not change with increasing size of the host or increasing total worm burden. Thyrsites atun have a higher proportion of larvae in the stomach wall (8-13%) compared to Trachurus spp. (< 4%). T. adunca larvae are found infrequently in the body cavity of all three species, on the pyloric caeca and in the stomach wall. Adults and larvae of T. adunca are found more commonly in the alimentary canal, indicating that these teleosts are more important as definitive hosts in the life cycle of this anisakid. P. decipiens larvae are found only in Thyrsites atun and occur mainly in the muscles (98.5%). No quantitative pathogenic effects of anisakid infestation on these teleosts hosts were detected. The main factors influencing the infestation of the three teleost species are age of the host, locality and season. Sex of the host and depth (over the continental shelf, 0-250 m) are not important. A. simplex infestation increased with age in all host species examined, and was higher in Trachurus declivis from the southern-most locality, suggesting the existence of at least two distinct populations of this species. Significant differences in infestation of Thyrsites atun with P. decipiens suggests that this anisakid may be more common in southern localities also. The infestation of Thyrsites atun by larval and adult T. adunca in the alimentary canal is most influenced by season and closely related to diet. Nematode samples were obtained from the marine mammals Arctocephalus forsteri, Kogia breviceps and Phocarctos hookeri. Adult A. simplex were recorded from A. forsteri (a new host record) and Kogia breviceps; preadults from Phocarctos hookeri. Adult P. decipiens were recorded from Phocarctos hookeri; preadults from Arctocephalus forsteri and K. breviceps. Other anisakids found were Anisakis physeteris (Baylis 1923), Contracaecum osculatum Rudolphi 1802 and Pseudoterranova kogiae (Johnston and Mawson 1939) Mosgovoi 1951. These records are all new for the New Zealand region except P. decipiens from P. hookeri and C. osculatum from Arctocephalus forsteri. A. simplex and C. osculatum were found associated with gastric ulcers in Arctocephalus forsteri.</p>

scholarly journals Studies on the Life Cycle of Some New Zealand Anisakidae (Nematoda)

2021 ◽  
Author(s):  
◽  
Rosemary Jennifer Hurst
Keyword(s):  
Life Cycle ◽  
New Zealand ◽  
Body Cavity ◽  
The Body ◽  
In Vitro Cultivation ◽  
Free Living ◽  
Larval Stages ◽  
Factors Influencing ◽  
Phocarctos Hookeri

<p>The life cycle of Anisakis simplex in New Zealand waters is described from observations on the morphology, distribution and behaviour of free-living and parasitic stages. Comparison with the life cyles of two other anisakids, Phocanema decipiens Myers 1959 and Thynnascaris adunca Rudolphi 1802 shows differences in distribution, degrees of host specificity, the status of invertebrate hosts, the factors influencing infestation levels of teleost hosts, and the location and pathological effects of infestation. Larval stages occurring in intermediate and paratenic hosts were identified by comparison of larval and adult morphometrics. A. simplex larvae were also positively identified by in vitro cultivation through to adults. Some morphometric variations compared to overseas descriptions are apparent. The ventriculus of A. simplex larvae is shorter relative to body length and the intestinal caecum of P. decipiens is longer relative to ventriculus length. Egg and free-living larval stages were obtained from in vitro cultivation of (A. simplex) and collection of eggs from mature adults from definitive hosts (T. adunca). Eggs of P. decipiens were not obtained. Eggs of A. simplex and T. adunca hatch in 8-11 days at 15 [degrees] C. A. simplex eggs hatch in 6 days at a temperature of 22 [degrees] C and did not hatch in 16 days at 10 [degrees] C. Eggs and free-living stage III larvae of A. simplex and T. adunca are similar in morphology with little differentiation of internal structures. Examination of the stomach contents of pelagic fish infested with anisakids indicated that possible intermediate hosts of A. simplex are the euphausiid Nyctiphanes australis and the decapod Munida gregaria. Possible hosts of T. adunca and M. gregaria are a wide variety of smaller zooplanktonic groups, e.g. decapod larvae and copepods. Larvae of A. simplex were found in one of 8850 N. australis; larvae of T. adunca were found in 69 of 3999 chaetognaths (Sagitta spp.) a medusa and a decapod larva. These larvae are morphologically similar to Stage III larvae from teleosts. No anisakids were found in 3956 Euphausia spp., 1147 M. gregaria and 740 prawns. Twenty five T. adunca larvae and adults were found in 818 freshly eaten M. gregaria in teleost stomachs, indicating that this invertebrate may act as a paratenic and a definitive host. Experimental infection of N. australis and M. gregaria with stage II larvae of A. simplex and T. adunca was unsuccessful. The location of anisakid infestation in three pelagic teleost species, Thyrsites atun, Trachurus novaezelandiae and Trachurus declivis is described. A. simplex larvae are found mainly in the body cavity of all species, at the posterior end of the stomach, with less than one percent occurring in the musculature. Distribution of A. simplex larvae does not change with increasing size of the host or increasing total worm burden. Thyrsites atun have a higher proportion of larvae in the stomach wall (8-13%) compared to Trachurus spp. (< 4%). T. adunca larvae are found infrequently in the body cavity of all three species, on the pyloric caeca and in the stomach wall. Adults and larvae of T. adunca are found more commonly in the alimentary canal, indicating that these teleosts are more important as definitive hosts in the life cycle of this anisakid. P. decipiens larvae are found only in Thyrsites atun and occur mainly in the muscles (98.5%). No quantitative pathogenic effects of anisakid infestation on these teleosts hosts were detected. The main factors influencing the infestation of the three teleost species are age of the host, locality and season. Sex of the host and depth (over the continental shelf, 0-250 m) are not important. A. simplex infestation increased with age in all host species examined, and was higher in Trachurus declivis from the southern-most locality, suggesting the existence of at least two distinct populations of this species. Significant differences in infestation of Thyrsites atun with P. decipiens suggests that this anisakid may be more common in southern localities also. The infestation of Thyrsites atun by larval and adult T. adunca in the alimentary canal is most influenced by season and closely related to diet. Nematode samples were obtained from the marine mammals Arctocephalus forsteri, Kogia breviceps and Phocarctos hookeri. Adult A. simplex were recorded from A. forsteri (a new host record) and Kogia breviceps; preadults from Phocarctos hookeri. Adult P. decipiens were recorded from Phocarctos hookeri; preadults from Arctocephalus forsteri and K. breviceps. Other anisakids found were Anisakis physeteris (Baylis 1923), Contracaecum osculatum Rudolphi 1802 and Pseudoterranova kogiae (Johnston and Mawson 1939) Mosgovoi 1951. These records are all new for the New Zealand region except P. decipiens from P. hookeri and C. osculatum from Arctocephalus forsteri. A. simplex and C. osculatum were found associated with gastric ulcers in Arctocephalus forsteri.</p>

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